Subtractive EQ-ing removes “bad” or unnecessary frequencies from a track to free up headroom and make the “good” in your track stand out more. When doing subtractive EQ, you typically want a narrower or “tighter” bandwidth to only affect the bad frequencies you want to reduce (except for low cut filters).

TIP: a great way to find bad frequencies is to put in a really large boost, tighten it up by having a narrow bandwidth and move it along the frequency line until you hear some unpleasant/harsh sounding frequencies.

Example 1: You might put a low cut filter at 95Hz on your vocals as you can’t hear the frequencies below 95Hz anyway however you free up those frequencies for your bass and drums.

Example 2: You might find that at 328Hz, there’s a harsh distortion on your vocals, so by cutting this frequency by 3 or 6 db, you eliminate this unpleasant sounding frequency.